Computer disks can NOT get damaged in an x-ray machine. X-ray machines do not generate a magnetic field. The disks are perfectly safe going through.
In fact, if you don't put the disks through the x-ray, you have to go through the metal detector, which CAN damage disks (because they do generate a magnetic field-- that's how they detect metal!)
Film is a bit trickier. Higher ISO films are more sensitive to light. Most airports will tell you that their x-ray machines are safe for ISO 1600 and below, but if they have to scan multiple times, the x-ray exposures add up on the film. Regular ISO 400 film from your vacation will be perfectly fine.
However, DO NOT KEEP FILM in the bags that you check. Checked baggage is scanned with much higher power x-rays than carry-on baggage.
Go here for more info, and examples of the damage that x-rays can do:
http://www.vad1.com/photo/x-ray-exper.html
So, in a nutshell, you need to worry about film more than computer disks.